of ludwigshafen-on-the-rhine



UNITED STATES PATENT OFFICE.

RENE 301m, on LUDWIGSHAFEN-ON-THE-RHINE, BAVARIA, Assreuon TO THE nADIscI-IE ANILIN AND soDA FABRIK, on MANNI-IEIM, GERMANY.

ALlZARlNE-GREEN SU LPHO-ACID.

SPECIFICATION forming part of Letters Patent No. 401,635, dated April 16, 1889.

Application filed October 31, 1888. Serial No. 289,677. (Specimens) To all whom, it may concern: ward be collected upon a filter, pressed, and

Be it known that I, RENE: BOHN, a citizen dried. of Switzerland, residing at Ludwigshafen-on- Alizarine-green sulpho-acid prepared as the-Rhine, in the Kingdom of Bavaria and before described presents the following char- Empire of Germany, have invented new and acteristic properties: In its solid state it has useful Improvements in the ll'lanufacture of the appearance of a crystalline powder con- Alizarine- Green Sulpho-Acid, of which the sisting of small needle-shaped crystals posfollowing is a specification. sessing a metallic luster. It is readily sol- My invention relates to the manufacture uble in water. The aqueous solution has a IO of an improved dye-stuff or coloring-matter bluish green color, which changes into red produced by the action of moderatelystrong upon the addition of mineral acids. Alkaline fuming sulphuric acid at an elevated tempercarbonates produce blue saline compounds, ature upon alizarine-green'. While caustic alkalies form green alkaline My improved dye-stuff or coloring-matter salts, which are not precipitated from their 15 is termed alizarine-green sulpho-acid, in aqueous solutions by adding thereto an exorder to indicate by this name both its chemi- -cess of caustic alkali. cal constitution and its general behavior, Alizarine-green sulpho-acid resembles alizwhich correspond to those of a true and arine blue-green in its general aspect; but stable sulphonated derivative of alizarineit may be readily distinguished from the same 20 green. by its superior degree of solubility in water,

In carrying out my invention I may employ and by the dingy-brown color of its solution alizarine-green either in its finishedmercanill B D W lph acid, the corretile condition orin the state of its solution in sponding solution of alizarine-blue-green exsulphuric acid-such as results from the suchibiting a bright-purple color. Fuming sul- 25 cessive treatment of alizarine-blue with sulphuric acid containing about twenty-three phuric anhydride and concentrated sulphuric per cent. of free anhydride dissolves alizarineacid in the process of preparing alizarinegreen sulpho-acid with a grass-green color, green described in my former application for While the solution of alizarine-blue-green in Letters Patent, filed on the 18th day of Octothe same solvent possesses a blue-green tint.

30 her, 1888, Serial No. 288,429. Alizarine-green sulpho-acid is readily con- The following is an example of the manner vcrted by treatmentwith the bisulphites of in which alizarine-green may be converted potash, soda, or ammonia into bisulphite cominto its hereinbef0re-named sulpho-derivapounds, soluble in water and capable of being tive: About ten parts, by weight, of dry and employed in dyeing and printing in a similar 35 finely-divided alizarine-green are gradually manner as the known analogous bisulphite added to about two hundred parts, by weight, compounds of alizarineblue. of filming sulphuric acid containing about Alizarine-green sulpho-acid produces upon from eight to ten. per cent. of free anhydride. Wool which has received a chrome mordant Throughout this operation the mixture or green shades similarto those of alizarine-green 40 solution thus prepared should be well agiitself. tated, and then its temperature is to be raised lVhatI claim as new, and desire to secure by to about from to about centigrade, Letters Patent, is 4 and maintained thereat for abouti'our or five As a newprod act, the coloring-matter or dyehours, or until a sample of the product has stuff (alizarine-green sulpho-acid) which is 45 become practically soluble in water. This produced by the action of moderately-strong 5 point being arrived at, the result of the opfuming sulphuric acid at an elevated tempereration is then poured into water, and the soature upon alizarine-green, and the chemical lution thus obtained is filtered and precipiconstitution and general behavior of which rated by the addition of common salt. The correspond to those of a true and stable suli 50 precipitate of the coloring-matter may afterphonated derivation of alizarine-grcen hav- 10o ing the following characteristics: In its solid state it has the appearance of a crystalline powder consisting of small needle-shaped crystals possessing a metallic luster; its aqueous solution has a bluish-green color, which changes into red upon the addition of mineral acids; alkaline carbonates produce blue saline compounds, While With caustic alkalies it forms green alkaline salts which are not precipitated from. their aqueous solutions by adding" thereto an excess of caustic alkali;

its solution in concentrated sulphuric acid has a dingy-brown color, and its solution in fuming suphuric acid containing about twenty-three per cent. of free anhydride has a grass-green color; upon chrome-1nordanted Wool it produces green shades.

In testimony whereof I have hereunto set my hand in the presence of tWo subscribing Witnesses.

R. BOHN.

Vitnesses:

I-I. FIRMANN, HERM. HAUT. 

